1 // SPDX-License-Identifier: GPL-2.0-only
3  * Copyright (C) 2021 - Google LLC
6  * Driver for Open Profile for DICE.
9  * generated by the Open Profile for DICE measured boot protocol. The memory
15  *     fd = open("/dev/open-dice0", O_RDWR);
29 #define DRIVER_NAME "open-dice"
40 	return container_of(filp->private_data, struct open_dice_drvdata, misc);  in to_open_dice_drvdata()
47 	mutex_lock(&drvdata->lock);  in open_dice_wipe()
48 	kaddr = devm_memremap(drvdata->misc.this_device, drvdata->rmem->base,  in open_dice_wipe()
49 			      drvdata->rmem->size, MEMREMAP_WC);  in open_dice_wipe()
51 		mutex_unlock(&drvdata->lock);  in open_dice_wipe()
55 	memset(kaddr, 0, drvdata->rmem->size);  in open_dice_wipe()
56 	devm_memunmap(drvdata->misc.this_device, kaddr);  in open_dice_wipe()
57 	mutex_unlock(&drvdata->lock);  in open_dice_wipe()
62  * Copies the size of the reserved memory region to the user-provided buffer.
67 	unsigned long val = to_open_dice_drvdata(filp)->rmem->size;  in open_dice_read()
73  * Triggers a wipe of the reserved memory region. The user-provided pointer
80 		return -EIO;  in open_dice_write()
93 	if (vma->vm_flags & VM_MAYSHARE) {  in open_dice_mmap()
95 		if (vma->vm_flags & VM_WRITE)  in open_dice_mmap()
96 			return -EPERM;  in open_dice_mmap()
101 	/* Create write-combine mapping so all clients observe a wipe. */  in open_dice_mmap()
102 	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);  in open_dice_mmap()
104 	return vm_iomap_memory(vma, drvdata->rmem->base, drvdata->rmem->size);  in open_dice_mmap()
117 	struct device *dev = &pdev->dev;  in open_dice_probe()
122 	rmem = of_reserved_mem_lookup(dev->of_node);  in open_dice_probe()
125 		return -EINVAL;  in open_dice_probe()
128 	if (!rmem->size || (rmem->size > ULONG_MAX)) {  in open_dice_probe()
130 		return -EINVAL;  in open_dice_probe()
133 	if (!PAGE_ALIGNED(rmem->base) || !PAGE_ALIGNED(rmem->size)) {  in open_dice_probe()
134 		dev_err(dev, "memory region must be page-aligned\n");  in open_dice_probe()
135 		return -EINVAL;  in open_dice_probe()
140 		return -ENOMEM;  in open_dice_probe()
146 			.name	= drvdata->name,  in open_dice_probe()
152 	mutex_init(&drvdata->lock);  in open_dice_probe()
155 	snprintf(drvdata->name, sizeof(drvdata->name), DRIVER_NAME"%u", dev_idx++);  in open_dice_probe()
157 	ret = misc_register(&drvdata->misc);  in open_dice_probe()
160 			drvdata->name, ret);  in open_dice_probe()
172 	misc_deregister(&drvdata->misc);  in open_dice_remove()
177 	{ .compatible = "google,open-dice" },
193 	/* DICE regions are optional. Succeed even with zero instances. */  in open_dice_init()
194 	return (ret == -ENODEV) ? 0 : ret;  in open_dice_init()